I run into the same problem. What really blows my mind is that cars have been using metric bolts for decades now and they are still a pia to find.
Go into any hardware store and you will find a whole aisle of standard bolts and nuts in every size and grade imaginable.
Look for metric in that same hardware store and you may find a small rack with few to none in the size you need and for sure not the 10.9 hardness you need for suspension bolts.
Anyway good find thanks